A method of designing multielectrode‐pair monolithic filters on high‐coupling piezoelectric plates

Abstract

AbstractIn the design of monolithic filters using multiple energy‐trapped resonators on a piezoelectric plate, the conventional method uses operating parameter theory in lumped‐element equivalent circuits. This method cannot, however, be used for designing wideband monolithic filters employing high‐coupling piezoelectric plates such as piezo‐electromagnetic material and LiTaO3 because the error introduced by the lumpedelement equivalent circuit is large. Therefore, this paper proposes a new method using the distributed‐element equivalent circuit, which is suitable for image parameter design theory. First, it is pointed out that in the design of monolithic filters based on the image parameter method which is adopted for designing multimode filters, the resonant and antiresonant arrangement method is difficult to apply to high‐coupling piezoelectric plates. Next, we point out that in order to deal with this problem a new resonant and antiresonant frequency arrangement method is suitable for high‐coupling plate filters and thus good filter properties can be obtained.